1981 Merc 140 noob carb questions

[dazzy]

I just got a 1981 merc 140 (carb #1351-7355).

Haven't run it yet as I need to replace the shift cable this weekend. But I was giving it a good onceover, checking connections, fittings, everything I could without running it and noticed what looks to be a vacuum connection right under the flame arrestor. Is there supposed to be a hose connected to that? I've been searching for a while now with no luck.
That leads to the second question, while checking the mechanics of the carb I noticed the butterfly valve doesn't open when increasing throttle (either by the cable on the carb or the lever). It's been 25 years since I've worked on an engine without electronics for forgive my ignorance nd bad memory. Is the butterfly valve vacuum operated or am I missing a link between the throttle and the pump rod(?), or is everything fine and the valve is opened by suction when the engine is running.

Any help is greatly appreciated

 

[Bt Doctur]

Re: 1981 Merc 140 noob carb questions

that fitting takes the hose from the mechanical fuel pump to divert the gas from a ruptured diaphram into the carb instead of the bilge where you blow up. need the engine serial number to get you to the correct manual but this version might help identify the parts.
http://www.boatfix.com/merc/Servmanl/13/13B5R2.PDF

 

[thumpar]

Re: 1981 Merc 140 noob carb questions

The butterfly that you may be looking at is the choke. It is close to the top and don't open with the throttle. The throttle butterflies are at the bottom of the carb.

 

[dazzy]

Re: 1981 Merc 140 noob carb questions

Thanks for the help, I see it now, there is an empty threaded hole near the bottom of the fuel pump at an angle. Not sure why that's missing.

The engine serial number is5763016 mcm140 181 cid




So it should be 1B and 1C in this diagram? https://www.sunsetmarine.com/outboa...URETOR?zenid=838212afb2e9e14c00499c3465046afd